Blending of organic polymers with inorganic fillers is well known. Blending typically serves to improve the mechanical properties of the polymer as well as to extend the polymer through use of generally less expensive fillers. Typical fillers include talc, mica, certain calcium carbonates, glass fibers, gypsum and others as disclosed in published Japanese Patent Application J59064647-A. The use of such fillers in polyolefins is disclosed in published Japanese Patent Application J59147035-A. The use of flaky fibers, particularly mica, in thermoplastic resins such as polyolefins is shown by Ueeda et al., U.S. Pat. No. 4,555,439.
The ease with which blends of an organic polymer and an inorganic filler are produced and processed is greatly dependent upon the physical properties of the polymer and the filler as well as the extent of interaction between the components of the blend. Particularly important is the degree of adhesion between the polymer and the filler, especially when the polymer blend is to be employed in the production of shaped articles or articles which are to be subjected to mechanical or thermal stress. Improvement in important mechanical properties such as tensile strength, stiffness, ductility, and high heat distortion temperature result when a relatively high degree of adhesion occurs between the polymer and the filler. Lack of adhesion can be sufficiently troublesome so as to require the addition of cross-linking agents to overcome the problem and result in satisfactory mechanical properties.
The above two published Japanese Patent Applications require the use of a silane cross-linking agent in order to obtain good mechanical properties when a number of inorganic fillers including mica are blended with polyolefins. Wang, U.S. Pat. No. 4,066,604 teaches the preferred use of nitrophenylenes or sulfonated polyphenylenes as cross-linking agents when mica is blended with certain branched polyphenylenes.
An easily observed measure of the degree of adhesion, or lack of adhesion, is the phenomena of whitening of a polymer composition under stress or distortion. The above published Japanese Patent Applications teach that resistance to whitening is a desired property of the disclosed compositions which employ cross-linking agents. Ueeda, U.S. Pat. No. 4,555,439 prepares rolled sheets of specific crystallinity and cites lack of whitening as an improved property.
U.S. Pat. No. 4,317,765 to Gaylord teaches that about 23 different hydroxyl-containing fillers can be added to about 76 different thermoplastic polymers. Among the fillers is mica and among the polymers listed is a copolymer of carbon monoxide and ethylene, with the structure of the copolymers being omitted. Gaylord further states that the properties of polymer compositions are improved only if a coupling or compatibilizing agent is employed in the compositions. Having established the need for a coupling agent or compatibilization process, Gaylord sets forth two methods of accomplishing the desired compatibilization through the use of coupling agents.
The class of polymers of carbon monoxide and olefin(s) has been known for some time. Brubaker, U.S. Pat. No. 2,495,286, produced such polymers of relatively low carbon monoxide content in the presence of free radical initiators, i.e., peroxy compounds. G.B. 1,081,304 produced similar polymers of higher carbon monoxide content in the in the presence of alkylphosphine complexes of palladium salts as catalyst. Nozaki extended this process to produce linear alternating polymers by the use of arylphosphine complexes of palladium moieties and certain inert solvents. See, for example, U.S. Pat. No. 3,694,412.
More recently, the class of linear alternating polymers of carbon monoxide and at least one ethylenically unsaturated hydrocarbon, e.g., ethylene or ethylene and propylene, has become of greater interest in part because of the greater availability of the polymers. These polymers, often referred to as polyketones or polyketone polymers, have been shown to be of the repeating formula --CO--A-- where A is the moiety of unsaturated hydrocarbon polymerized through the ethylenic unsaturation. For example, when the hydrocarbon is ethylene the polymer is represented by the repeating formula --CO--CH.sub.2 --CH.sub.2 --. The general process for the more recent production of such polymers is illustrated by a number of published European Patent Applications including 121,965, 181,014, and their U.S. equivalents, U.S. Pat. No. 4,835,250 and U.S. Pat. No. 4,818,810. The process typically involves a catalyst composition formed from a compound of a Group VIII metal selected from palladium, cobalt and nickel, the anion of a strong non-hydrohalogenic acid and a bidentate ligand of phosphorus, arsenic or antimony.
The resulting polymers are relatively high molecular weight thermoplastics having established utility in the production of shaped articles, such as containers for the food and drink industry, which are produced by processing the polymer according to known methods. For some particular applications it has been found desirable to have properties for a polymeric composition which are somewhat different from those of the polyketone polymers. It would be of advantage to retain the desirable properties of the polyketone polymers and yet improve other properties. These advantages are often obtained through the provision of a polymer blend. Reinforcing a polymer with a filler often provides a less expensive product, in addition to desirable properties.
It is an object of this invention to provide blends of a polyketone polymer filled with mica which exhibit desirable properties. It is a further object of this invention to prepare such mica-filled compositions without the use of a coupling or compatibilizing agent commonly used with other filled polymer compositions.